Electrical connectors may be provided with a cylindrical dielectric insert member which carries one or more electrical contact elements adapted for engagement with cooperable contact elements similarly carried in a cylindrical dielectric insert member on another part of the electrical connector. The insert members are carried within metal shells of cylindrical form which include various configuration for permitting rapid positive mating and unmating of the electrical contacts by linear or axial movement of the insert members and contacts toward each other. It is desirable that in mating relation the electrical contacts and the insert members be presicely positioned within the plug and receptacle shells and securely held against axial movement relative to the shells. The electrical engagement of the contact pin in the contact socket is dependent upon such positioning of insert members. The depth of such pin and socket electrical engagement is critical.
Prior proposed means for retaining an insert member within a connector shell have included interengaged or interlocked shoulders on the insert member and connector shell for limiting movement of the insert member toward the mating shell or in one direction. To retain the insert member in pressed relation against such shoulders, prior proposed connectors included bonding as by epoxy of the insert member to the shell, providing a lock ring for holding the insert member in a fixed relation with respect to the cooperable shoulders, or providing a threaded plug or ring which could be screw threaded into the shell into engagement with the insert member. In such bonding and lock ring prior proposed arrangements, assurance was lacking that the insert member was held in desired position. In prior screw threaded arrangements sufficient tightening of the nut, ring, or plug would move the insert member to selected position, however, radial space or clearance for adequate thread depth on the shell section was not always available. Further, such screw threading was slow; production assembly time was increased with resultant cost increases. Since such electrical connectors are often subjected to vibration, shock forces, drastic environmental changes, any variance permitted in the precise positioning of the insert member with its electrical contacts endangered reliability of operation.